This isn't the first time Charlie Brown has flown a kite, I think. It doesn't count as the beginning of the kite-flying-failure aspect of his character either, since all of the characters are holding (or jumping, or are tied to) some piece of string, and two are actually running with them.
Also different are the character's attitudes at the end. All of them are wearing a "dumbfounded" expression, including Charlie Brown. More frequently after causing a kite crash, Charlie Brown's expression is more like dismay, or disgust.
One thing I wonder about... in the last panel, three of the characters are sticking their tongues out. This is a bit of graphic shorthand sometimes used in comics (especially older ones) to represent dumbfoundedness or annoyance. But where did this convention get started? It doesn't seem like a particularly obvious connection to make, to stick out your tongue in the face of a blameless accident. How did this get invented? (While we're at it, when did "Z" become the universal signifying letter for sleep?)
Notice that Shermy is walking Snoopy here, making the dog's owner more doubtful again.
All of the current characters are represented in this strip except Linus.